The present invention relates generally to piston and cylinder assemblies particularly of the type suited for use as shock absorbers or compression struts.
In piston-cylinder units of this type, an elastically compressible tubular body serves as an axially compressible limit stop which becomes effective when the piston rod of the unit is essentially retracted into the cylinder assembly and prevents a hard impact of the piston rod assembly in the cylinder unit. During axial compression of the resilient tubular body, an annular chamber defined within the tubular body is reduced in size so that excess pressure of the enclosed air can be generated within this annular chamber which is closed by means of closing means on a cap assembly on the cylinder assembly.
It is desirable to allow this excess pressure to excape as much as possible in the region of the cap assembly because this is the most suitable location for providing appropriate passage means. On the other hand, it is desirable to prevent the excess pressure from having a negative effect on the sealing function of the seal of the guide and seal assembly.
In view of this, it is known to arrange on the outside of an annular bottom of the cap an embossed plate which is not integrated in the cap, the plate providing the passage means for bleeding the annular chamber. Radial bleeder ducts are formed in this plate by means of embossing.
This plate has been constructed with a relatively large diameter exceeding the diameter of the cap, so that the space to be provided for the piston-cylinder units, particularly when supported through this plate, is increased. In addition, the manufacture of the plate by means of embossing and subsequent mounting on the cap is cumbersome and expensive.
The present invention is directed toward the further development of a piston-cylinder unit of the aforementioned type wherein as little structure as possible is required for the closing means and for the bleeding function and wherein the diameter of the entire unit is not increased.